Speaker
Description
Massive galaxies, acting as gravitational lenses, can form greatly distorted images of background galaxies in so called strong lensing events. When background galaxy and lens are almost aligned along the line of sight, the image take the shape of an Einstein ring whose shape encodes basic properties of the lens. However, since lenses are not isolated objects in an otherwise perfectly homogeneous universe, these Einstein rings are sligthly altered by further weak lensing along the line of sight coming from the large scale matter distribution in the universe in front and behind the lens. This coupling between strong and weak lensing offers a novel opportunity to probe cosmic shear, in a regime that is not plagued by the same systematics as standard weak lensing shear. We will present this new method and its perspectives for the Euclid survey.
